chromium/third_party/blink/web_tests/external/wpt/css/filter-effects/css-backdrop-filters-animation-grayscale-ref.html

<!DOCTYPE html>
<title>CSS Backdrop Filters Animation: Blur Reference</title>
<link rel="author" href="mailto:[email protected]">
<style>
    .square {
        position: absolute;
        width: 100px;
        height: 100px;
        top: 100px;
        left: 100px;
        background: blue;
    }
    .filt {
        position: absolute;
        width: 200px;
        height: 200px;
        top: 50px;
        left: 50px;
        backdrop-filter: grayscale(50%);
    }
    .greenbox {
        position: absolute;
        width: 50px;
        height: 50px;
        top: 75px;
        left: 75px;
        background: green;
    }
</style>
<p>You should see a dark blue rectangle with a green box.</p>
<div class="square"></div>
<div class="filt">
    <div class="greenbox"></div>
</div>